The Troy MRF is the strongest user-installed free-floating rail system in the world. Troy MRFs are available for all M16/M4 weapon systems equipped with the original factory barrel nut. The MRF’s patented mounting system reinforces the barrel nut with a sturdy clamp and anti-rotation alignment lugs. Troy MRF BattleRails provide an uninterrupted rail extension and hand guard aligned perfectly with the host weapon’s flat-top receiver. Accepts Quick-Detach 360 Push Button Swivel. Troy MRF-R Rails - For all M16A1, A2, A3, A4 type carbines. Adds only 8.75 oz to weight of M16. Specifications: - Replaces the factory delta ring - Installation does not require removal of the front sight or barrel - Constructed from aircraft aluminum and finished in MIL-SPEC Type III hard coat anodize with Teflon - Accepts Quick-Detach 360 Push Button Swivel - Flat Dark Earth